In the Atomic Physics and laser spectroscopy lab, design and development of the experimental setup for the measurement of lifetimes of excited atomic and molecular states using high frequency deflection technique with a delayed coincidence single photon counting arrangement and cascade-photon-coincidence technique was done. A large number of levels of some inert gases, both neutral and singly ionized, are investigated with the help of this apparatus. Some of the atomic levels investigated are: 2p5nd (n=4,5) and 2p5ns (n=5,6) configuration of NeI, 3p44p and 3p44d configuration of ArII, etc. A time resolved laser spectroscopy (TRLS) setup for radiative lifetime measurement using selective pulsed laser excitation and time resolved observation of the reemitted fluorescence is under development.